This invention relates to a rotary cutting deck, namely to a cutting deck having at least one cutting blade that rotates in a substantially horizontal cutting plane, for use as part of a mower for cutting grass. More particularly, this invention relates to a cutting deck which discharges the grass clippings to the rear of the deck when the deck is configured in a grass discharge mode.
Mowers are known for mowing large areas of grass, such as those in parks, golf courses, athletic fields, and the like. Many such mowers comprise a self-propelled traction frame that is part of a vehicle on which the operator sits as the mower is operated. At least one cutting deck, and often a plurality of cutting decks, are attached to the traction frame to cut a swath of grass as the traction frame moves forwardly. These cutting decks are usually attached to the traction frame by various known suspensions or linkages that permit the cutting decks to float relative to the ground so that the cutting decks follow or adjust to the contours of the ground as they pass over the ground.
Rotary cutting decks are often used as the cutting decks in mowers of this type. Rotary cutting decks are so named not because the decks themselves rotate in circles, but because the decks house one or more rotary cutting blades that rotate in circles in substantially horizontal cutting planes. Single spindled decks are known in which a single cutting blade is contained within each cutting deck. Thus, when a mower is equipped with a plurality of single spindled decks, each individual deck will be ground following and will contain a single rotary cutting blade, the decks being staggered and overlapped with one another so that all the decks collectively cut a single swath of grass.
As grass is cut by a given rotary cutting deck, grass clippings are generated which are eventually deposited onto the ground, assuming they are not first collected in some type of grass bagging attachment. Some rotary cutting decks are designed specifically as mulching decks in which the grass clippings fall or are driven out of the deck in a generally downward direction through an open bottom face of the deck. Some mulching decks of this type carry various baffles or deflectors which extend downwardly from the top wall of the deck into the flow of the grass clippings circulating within the deck to assist or speed in the downward movement of the grass clippings out of the mulching deck. U.S. Pat. No. 5,133,176 to Baumann et al., assigned to The Toro Company, the assignee of this invention, shows a mulching deck of this type.
Dedicated mulching decks, namely decks which only mulch by confining the grass clippings within the cutting deck until they exit through the open bottom of the cutting deck, do not permit the side or rear discharge of the grass clippings. Some operators of equipment of this type prefer mowers which also have the ability to discharge the grass clippings in a generally horizontal path through or beneath the peripheral wall of the cutting deck as opposed to having the clippings be driven vertically downwardly as in a mulching deck. A rotary cutting deck is a side discharge deck where the grass clippings are discharged to one side of the deck while a rear discharge deck is one where the grass clippings are discharged to the rear of or behind the cutting deck. In mowers where a plurality of cutting decks are carried on a traction frame, rear discharge decks are typically preferred over side discharge decks.
Some cutting decks are convertible between mulching and grass discharge modes by virtue of removable or openable covers that can be used to block the grass discharge outlets to place the mower into a mulching mode. In the mulching mode, since the grass discharge outlet is blocked, the grass clippings must necessarily fall out through the open bottom of the cutting deck. The operator can easily convert this cutting deck to a grass discharge mode simply by removing or opening the cover blocking the grass discharge outlet provided in the peripheral wall of the cutting deck. When this is done, the natural horizontal circulation of the grass clippings inside the deck will cause the vast majority of the clippings to pass through the grass discharge outlet instead of falling out through the open bottom of the cutting deck. U.S. Pat. No. 4,226,074 to Mullet et al. shows a cutting deck convertible between a mulching mode, a side discharge mode, and a rear discharge mode.
In the mower shown in the Mullet et al. patent, the rear discharge mode is effected simply by opening a cover that normally blocks a rear discharge opening in each individual cutting chamber of the cutting deck. While this is effective in allowing the grass clippings to exit to the rear of the deck, no particular thought or design was given to effecting an even distribution of grass clippings behind the mower. Thus, in many prior art mowers such as that shown in the Mullet et al. patent, the grass clippings deposited to the rear of the cutting deck will often lie on top of the turf in large clumps or groups. This condition will be particularly present and noticeable when the grass being cut has grown fairly long such that the grass clippings themselves are fairly long and/or when the grass being cut is relatively wet.
There is an increasing tendency in the turf care area for the owners of the site being cut to require a highly finished and groomed look after the grass on the site is cut. In other words, once the mowing operation is completed, the presence of visible grass clippings or clumps of grass clippings on top of the turf is increasingly undesirable, even for mowers whose cutting decks are operating in grass discharge modes. Instead, grass clippings being discharged to the side or rear of a cutting deck are desirably spread out as evenly and as smoothly as possible. Rotary cutting decks which are capable of this are more desirable to the purchasers of such equipment.
One aspect of this invention relates to a rotary cutting deck for a mower which includes at least one cutting chamber formed by a top wall and a peripheral wall. A rotary cutting blade is carried in the cutting chamber for rotation in the cutting chamber. The cutting blade rotates about a substantially vertical axis in a substantially horizontal cutting plane when the cutting deck and rotary cutting blade are in operation. A grass discharge outlet is provided in the peripheral wall of the cutting chamber for allowing grass clippings to exit from the cutting chamber in a substantially horizontal path. In addition, a ramp is located adjacent at least the peripheral wall of the cutting chamber. The ramp has a progressively increasing depth between a front end and a rear end thereof. The front end of the ramp is ahead of the grass discharge outlet and the rear end of the ramp is located adjacent some portion of the grass discharge outlet.
Another aspect of this invention relates to a rotary cutting deck for a mower which includes at least one cutting chamber formed by a top wall and a peripheral wall. The cutting chamber has two front and two rear quadrants taken with respect to forward motion of the cutting chamber. A rotary cutting blade is carried in the cutting chamber for rotation in the cutting chamber, the cutting blade rotating about a substantially vertical axis in a substantially horizontal cutting plane when the cutting deck and rotary cutting blade are in operation. A grass discharge outlet is provided in the peripheral wall of the cutting chamber with the grass discharge outlet being located in at least one rear quadrant of the cutting chamber for allowing grass clippings to exit to the rear of the cutting chamber in a substantially horizontal path. A ramp extends downwardly from the top wall of the cutting chamber and has a progressively increasing depth between a front end and a rear end thereof. The front end of the ramp is located in a front quadrant of the cutting chamber and the rear end of the ramp is located in a rear quadrant of the cutting chamber. The ramp deflects grass clippings downwardly in the cutting chamber towards the grass discharge outlet.
Yet another aspect of this invention relates to a rotary cutting deck for a mower which includes at least one cutting chamber formed by a top wall and a peripheral wall. A rotary cutting blade is carried in the cutting chamber for rotation in the cutting chamber, the cutting blade rotating about a substantially vertical axis in a substantially horizontal cutting plane when the cutting deck and rotary cutting blade are in operation. A grass discharge outlet is provided in the peripheral wall of the cutting chamber for allowing grass clippings to exit to the rear of the cutting chamber in a substantially horizontal path. A generally vertical vane extends downwardly within the cutting chamber and is angled so as to be non-concentric to the peripheral wall. The vane begins in advance of the grass discharge outlet and ends behind an entrance of the grass discharge outlet taken with respect to the direction of blade rotation.